(all) done up like a pox doctor's clerk

Dressed in a showy, flashy, or excessively fancy manner; overdressed. (The meaning of "pox doctor" in this context is not known.) Primarily heard in UK, Australia. He showed up to the interview done up like a pox doctor's clerk. You could tell he was eager to make a good impression—maybe a bit too eager. Why are you all done up like a pox doctor's clerk? We're only going to the movies. I'm all done up like a pox doctor's clerk because the CEO was supposed to visit our office today. But his plans changed, and now I just look like a fool.